1. Field of the Invention
The present invention relates to a reciprocal compressor, and more particularly to, an apparatus for preventing abrasion in a reciprocal compressor which can prevent abrasion from being generated between a cylinder and a piston linearly reciprocating in an inside space of the cylinder due to processing errors and assembly errors of components of the reciprocal compressor.
2. Description of the Background Art
In general, a compressor transforms an electric energy into a kinetic energy, and compresses refrigerants by the kinetic energy. The compressor is one of the major components of a refrigeration cycle system, and classified into a rotary compressor, a scroll compressor and a reciprocal compressor according to a compression mechanism for compressing refrigerants.
FIG. 1 is a cross-sectional diagram illustrating the reciprocal compressor. Referring to FIG. 1, the reciprocal compressor includes a casing 100 having a gas suction tube 110 and a gas discharge tube 120, a frame unit 200 disposed in the casing 100, a reciprocal motor 300 mounted on the frame unit 200, for generating a linear reciprocation driving force, a compression unit 400 for receiving the driving force of the reciprocal motor 300, and compressing a gas, and a resonant spring unit 500 for resonating the driving force of the reciprocal motor 300.
The frame unit 200 includes a front frame 20 for supporting one side of the reciprocal motor 300, a middle frame 220 for supporting the other side of the reciprocal motor 300, and a rear frame 230 coupled to the middle frame 220, for forming a space with the middle frame 220.
The reciprocal motor 300 includes an outside stator 310 fixed between the middle frame 220 and the rear frame 230, an inside stator 320 inserted into the outside stator 310 and fixedly coupled to the front frame 210, a mover 330 movably inserted between the outside stator 310 and the inside stator 320, and a winding coil 340 coupled into the outside stator 310. The mover 330 is comprised of a magnet 331 and a magnet holder 332 for supporting the magnet 331.
The compression unit 400 includes a cylinder 410 fixedly coupled to the front frame 210, a piston 420 having its one side movably inserted into an inside space of the cylinder 410, and its other side fixedly coupled to the mover 330, a discharge valve assembly 430 mounted on one side of the cylinder 410, for controlling discharge of refrigerants, and a suction valve 440 mounted on the end of the piston 420, for controlling flow of refrigerants sucked to the inside space of the cylinder 410.
The piston 420 is comprised of a cylindrical body unit 421 having a predetermined length and outer diameter, a flange unit 422 extended from the end of the cylindrical body unit 421 in the vertical direction, the magnet holder 332 of the mover 330 being coupled to the flange unit 422, and a suction passage 423 formed in the cylindrical body unit 421.
The discharge valve assembly 430 includes a discharge cover 431 for covering the inside space of the cylinder 410, a discharge valve 432 inserted into the discharge cover 431, for opening/closing the inside space of the cylinder 410, and a discharge spring 433 inserted into the discharge cover 431, for elastically supporting the discharge valve 432.
The resonant spring unit 550 includes a spring support means 510 fixedly coupled with the piston 420 and the mover 330, a front coil spring 520 coupled between the spring support means 510 and the middle frame 220, and a rear coil spring 530 coupled between the spring support means 510 and the rear frame 230.
Reference numeral 10 denotes a support spring and 411 denotes the inside space of the cylinder 410.
The operation of the reciprocal compressor will now be explained.
When power is supplied to the reciprocal compressor, the linear reciprocation driving force is generated by an electromagnetic interaction of the reciprocal motor 300, and transmitted to the piston 420 through the mover 330.
The piston 420 receives the linear reciprocation driving force from the mover 330, and linearly reciprocates in the inside space 411 of the cylinder 410. The suction valve 440 and the discharge valve 432 are operated due to the linear reciprocation of the piston 420 and a pressure difference between the inside space 411 of the cylinder 410 and the outside, for sucking refrigerants to the inside space 411 of the cylinder 410, compressing the refrigerants and discharging the compressed refrigerants. The discharged refrigerants are discharged from the reciprocal compressor through the discharge cover 431 and the discharge tube 120. The refrigerants are compressed by repeating the above procedure.
The front coil spring 520 and the rear coil spring 530 are contracted or relaxed by the reciprocation of the mover 330 and the piston 420, for elastically supporting the mover 330 and the piston 420 and generating resonance.
On the other hand, in order to improve compression efficiency of the refrigerants compressed in the inside space 411 of the cylinder 410, the reciprocal compressor must precisely maintain an assembly tolerance between the inside space 411 of the cylinder 410 and the piston 420 inserted into the inside space 411 of the cylinder 410.
However, as described above, in the reciprocal compressor, the mover 330, the piston 420 and the resonant spring unit 500 are assembled as one assembly and coupled to the other components. If processing or assembly errors of the components occur during the processes for processing each component of the assembly and the processes for coupling the components, as shown in FIG. 2, concentricity of the inside space 411 of the cylinder 410 is not identical to that of the cylindrical body unit 421 of the piston 420, and thus the inner walls of the inside space 411 of the cylinder 410 contact the cylindrical body unit 421 of the piston 420. Accordingly, the cylinder 410 and the piston 420 are abraded and the compressed refrigerants are leaked, which results in low compression efficiency.